Does Variable Access Use Dynamic Binding in Java?
No, variable access does not use dynamic binding in Java. Instead, variables are resolved at compile-time using static binding. However, methods use dynamic binding (runtime polymorphism).
Static vs. Dynamic Binding
Feature | Methods (Dynamic Binding) | Variables (Static Binding) |
Binding Time | Runtime (late binding) | Compile-time (early binding) |
Depends On | Actual object type | Reference type (declared type) |
Polymorphism? | Yes, overridden methods | No, variables are not overridden |
Example: Method vs. Variable Access
class Animal {
String sound = "generic animal sound";
void makeSound() {
System.out.println("Some animal sound");
}
}
class Dog extends Animal {
String sound = "bark";
@Override
void makeSound() {
System.out.println("Bark");
}
}
public class DynamicBindingExample {
public static void main(String[] args) {
Animal myAnimal = new Dog();
// Dynamic binding for the method
myAnimal.makeSound(); // Outputs: Bark
// Variable binding is static, not dynamic
System.out.println(myAnimal.sound); // Outputs: generic animal sound
}
}
Conclusion
Variables are statically bound → Resolved at compile-time based on reference type.
Methods use dynamic binding → Resolved at runtime based on actual object.
This is why overriding applies only to methods, not variables in Java.